This invention relates to digital loop carrier transmission systems.
In standard digital loop carrier transmission systems, such as the Subscriber Loop Carrier (SLC.RTM.) system, each channel unit (CU) interfacing with the customer provides service for two channels. In order to monitor testing and relay problems on the channels, present systems generally include a single 8-bit "health" register which can be read by a bank controller unit (BCU).
In newer systems, each unit will service four channels, as well as provide enhanced services such as inventory and automatic loss control. Such quad channel units should be compatible with existing systems, as well as provide additional information concerning the health of the additional channels. Further, it is desirable to minimize the time needed to address any registers on the units.